1. Field of the Invention
This invention relates to a light measuring device for measuring a quantity regarding light such as luminance, chromaticity or the like of a plane light source and a scanning optical system which can be utilized in the light measuring device.
2. Description of the Related Art
A technique is known wherein, in order to measure a luminance distribution, a chromaticity distribution or the like of a plane light source, a physical quantity or a psychophysical quantity such as luminance, chromaticity or the like at different portions of the plane light source such as a central portion, outer peripheral portions and so forth is successively measured. Japanese Patent Laid-Open No. 2004-93326. (hereinafter referred to as Patent Document 1) discloses a collection device for collecting optical information of a web such as a paper web. The collection device includes a galvano-mirror for successively deflecting light from different portions of the web to carry out scanning of the web, two slits for transmitting the light deflected by the galvano-mirror therethrough and, a spectrometer for spectralizing the light transmitted through the two slits. With the technique disclosed in Patent Document 1, measurement of light from a plane light source can be carried out from one position, that is, from a visual point.